Automatic expanding oil drill



D. H. MITCHELL" AUTOMATIC EXPANDING 01;; DRILL FiledOct. 22. 1923 4 Shedts-Sheet 1 I M/Q'Zckelb v 1532330 D. H. MITCHELL.

1923 4 Sheets-Sheet 2 Filed Oct 22.

AUTOMATIC EXPANDING OIL DRILL Z 9 5 Wo. J 3 4 W w 0 Z w 9 M, D w; 6 Z M 2 5 if :2 1% w Z Z f 55 a 1 w 2% Q 5 f X 1 a 0 0 w 1 iii! 1! k I 1 l iail Z 2 9 H? m- 7 5 j 4 I| v O V KKK/J7 7 m 6 7 A a 5 Q1 2 7 Z w 7 m April 7, 1925. 53m? D. H. MITCHELL AUTOMATIC EXPANDING, 01L DRILL Filed 001;. 22. 1925 -4 Sheets-Sheet 4 .Inx? cantor attorney 7 .Pntented Apr. 7, 15125.

. tsezcso outrun sreresrATnnT orr ce;

no'rmnn I romnLEY HENRY MITCHELL, 0F CHATTANOOGA, TENNESSEE, ASSIGN'OR 0i? ONE-HALF .5 W. HOWCDTT, OF NEW ORLEANS, IfiUIS-IANA.

AUTQMATIC FXEPALWWG OIL DBILL.

Application flied octoherfift, tees. SerisL no. 670,170.

'Toall whom it may concem:

' Be it known that I, DONALD E. Mrrcnnnn, '21 citizenof the United States of- Americs, residing at Chattanooga, in the county of 5 Hamilton and State of 'lennessee; have in vented certain new and useful improvements in Automatic Expanding Oil Drills; and I do hereby declare that the following is a full, clear," concise, a 1d exact description of W the invention, such as will enable others skilled irhthe art t which'it eppertains or; make enclose the same. I

This invention relates to improvements in rotary drills, having for an object to pro 15 vide an automatic expanding rotary oil well drill capable of being operated by either the drill stem or casing of well drilling rigging and which, when in operation, will positively prevent disengagementof the cutters orreamers, the drill being automatically locked to the casing or stem and when desired, may be readily disconnected therefrom in order that it may I ,hore without necessity of removing the drill g stern or'casing.

- ltis also an object ofthe invention topro:

'vide the drill with novel forms of automatically operable locking devices for connecting the drilllto a casing or stem and for 1:0 securing the drill body in a fixed position with respect to the casing or stem in order thet the cutters or reamers Wlll he rigidly remined in extended operative positions, but

which, with disengagement of their locking 35 means, may he moved to retracted or inoperative positions to allow Withdrawal of the drill from such casing or stem. I

It is likewise an object of the invention to provide a drill body having the-upper portion of the drill soiormed as to per'mitof its.

driving connection to a casing or'stcm, thus allowing of the transmission of rotary motion thereto. i v

- Another and'cqunlly important object of the invention may be stated to reside in providing the drill with an over-shot devicc' which when lowered into engagement with the drill will serve to nutometicallyrelease I the locking means and simultaneously," be. '50 automatically connected to a portion of the be elevated from drill whereby the same may removed from the casing or stem and thus,

the bore for various purposes I I Yet another object f the invention is to be withdrawn from the provide a drill having the so-called rock. rollers or cutters mounted thereon in a manner. such as [will permit the same to effectually cut through either rock or earth or mud, such cutters having means on the same which will prevent the passage of grit or send into engagement with their hearing surfaces nnd causing premature deteriorationof the same. r I

A further object of. the invention is to provide the drill with novelty nrrnnged'i water Ways or ducts adapted to convey and." discharge water onto the cutters of the drill during their. operation whereby to cool the same. A still further object of the invention-is-= v to provide the drill with cutting end reaming devices which when in operation will. serve to effectually out the dirt or mud and. then plaster or-smooth tlie wa'ils of the hero or hole. Other objects will be in I ertobvious and in art pointed out hereinmtcr. I n'order that the invention end its mode 1 of operation may be readil understood loy persons skilled in the art, have in the accompanying illustrative drawings. and in; the detailedgfollowingdcflrigtggn based thereon, set out one possihle m imcnt of thesmne. I V 1 5 Inthese'drawings: i Figure 1 is a side elevation of. the improved drill;

Figure 2 is a he thereof, taken atsu stantic to the Figure 1;

Figure 3 is a longitudinal section through the improved drill; m

Figure 4 isle similar section t nken-on the lincHofFigure3;" 'tj e 1 I Fi ure 5 is an enlarged fragmentary longitnd inal section through th drill and the over shot grapple device, showing the mannor in which this latter device is adapted entery side elevation ly right angles 'to he connected to thedrill;

l igure 6 is a detail in perspective of the I i the slide bar;

disassembled fragmentaryshowing. the manner in bars are connected to' the lower portion lower portion of Figure 7 is a detail in perspective whichthe clamping the lateral extensions of of the slide bar;

Figure 8 is a detail, partly in section at theform of cutter employed;

. i l llmbt I Figure 9 is a side elevation of the form of reamer;

Figure 10 is a front elevation of the same;

Fl 11 is a transvei' section taken on the line 11-41 of Figur 2 Q; r

F re: 12 iaja similarviewtaken on the $12 M Figure 9;

Fi ure 13is a transverse section through the ower portion of the drill body; and, l igui'eld isadragmen tary detail in section showing the mounting-0f the cutter elements 'upon'the'drill head and cutters.

Having-more particular Reference to the drawhigs, in 1 connection With which like characters of reference will designate corre's di arts'throughout, the im roved dril may ie stated to compriseabo y. portion indicated in its entirety by the numeral 1, the upper portion of which is formed hexagonal or similarly shaped, as indicated at 2, while the lower portion thereof is reduced and c lindrical, as indicated at 3 a longitudinaly" disposed upwardly opening way 4 being formed in the drill body 1 havin the lower portion thereofenlarged as in icated at 5 and formed with diametrically disposed substantially rectangularly shaped openings 6. The lower portion or end of the drill body 3 is provided with a screw threaded pocket adapted lobe engaged by a drill bit hereinafter more fully described.

Edlidably received in a portion 'of the longitudinal w a is a slide rod 7 having a ,screw threaded pocket formed in the upper end thereof whereby to receive the screw threaded lower end of a reduced rod 8 pass ing through an opening formed in the web or shoulder portion 9 within said way 4 and having engagement at its upper end with an enlarged rod 10, the upper; end of which ex tends for a distance above the drill body 1 and is provided with notches 01' teeth 11 in its 'opposite sides. Anexpansible coiled spring 12 is arranged about the reduced rod 8 and has bearin r at one end upon an adjacent portion of web or shoulder 9, while its remaining and 'bears upon the adjacent end of the slide rod 7. Thus, it will be undcrstmid that the spring 12will normally exert a downward thrust upon the slide rod 7 and in consequence, will serve to normally retain the rod in its lowermost position.

The upper or enlarged portion of the drill body 1, as heretofore stated, is hexagonal or similarly shaped and is adapted to he snugly I,t:(50l\(*(l.lli the lower end of a correspondingly shaped drill stem 3 monly'uscd in connection with oil well drills v cti sln order that the enlarged hexagonal portion of the drill body 1 will be positively ocked with respectto'thelower end of the drill stem 13" and in consequence, will permit the transmission of rotary drilling !ll()- tion thereto, diametrically positioned bolts coin 14 are slidably mounted in the upper part of said portion 2, as-shown inthe Figures 3 and fiend are normally thrust outwardly by 'means of expansible coiled springs 15 engaged about the inner portions of the same and having their inner 'ends resting upon shoulders 16 formed adjacent the openings rcwiving such bolts. Levers 17 are mounted within a pocket 18 formed in the upper portion 2 of the drill body 1 in proximity to the inner ends of the several bolts 14 and are connected thereto, so that with movementof the same in one direction, inward pulls will be imparted to their respective bolts 14,, thus drawing the same to retracted positions with respect to the upper portion 2 of the drill bod The outer ends of these bolts 14 are adapted to be engaged, at times, in ,keepers or pockets 19 formed at diametrically opposite-points within the drill stem 13 and hence, it will be understood that with engagement of the outer ends of the bolts 14 therein, a locking connection as between thedrill body 1 and said drill stem will be effected. However, when the bolts 14 are moved to their retracted positions, these pockets 19 will b'e disengaged and in consequence, connection between the drill body and the drill stem will be interrupted and therefore, relative movement as between the two elements will be permitted.

As additional means for effecting the locking connection between the ,drill bod 1 and the drill stem 13, diametrically isposed pins 20 having rounded heads formed on their outer ends are slidably mounted in pockets provided therefor in the portion 2 of the drill body 1 and are normally thrust outward through the medium of expansible coiled springs 21 arranged thereabout and having' certain of thoir ends bearing upon shoulders formed in saidipoclcet, as shown in'th'e Figure-33. Complementally formed recesses or pockets-are formed in adjacent portions of the drill stem 13 and in consequenw, with alignment of the same with the rounded heads ofthe pins 20, said/pins will be permitted to enter the same and thereby all'ord additional connection between the drill body and the drill stem;

Vertically slidahle pins 22am mounted in the upper end of the portion 2 ol' the drill body 1 upon the opposite sides of the rod 10 and carry wedge-shaped shoes 33 upon. their lower ends; these pins being normally held in their uppermost positions by means of expansible coiled springs 24. re-

reived about the reduced lower ends of said pins 22 and in the pockets receiving the same, the lower ends of said springs having bearing upon tlieflanged or shouldered portions of the pockets for the pins 22. I

'llitha view towards'providin-g means for engaging the drill body 1 and removing the same, at times, from the drill stem 13, 1

i like connection engaging the upper sponding in size mally inwardly about-'expansible coiled dicated in its entirety by the numeral 25,

comprising a metal body having a cable thereof, as indicated by'the numeral 26, while a downwardly 'ope'ningpocket 27- is formed in the under side thereof correand shape to the upper e xtended porti'on ofthe rod and adapted to snugly receive the same therein. or-

thrusted bolts "or pinsf28 are slidably-mounted' in horizontally arranged openingsbr pockets-formed in the body oi-the' overhot 25 andreceive theresprings 29 serving to thrust thereto; the or bolts being pivot- 30 having their impart-such inward inner ends of. the pins ally connected to levers free extremities normally arranged in verti- "provided with openings accessible from the exterior por-.

cally disposed ways 31 formed at diametrically opposite points in the lower or under side of the under-shot inproximity to its outer portions. In this connection, it

is to he noted-that the vertical ways 31 are laterally extending branch tion of the over shot 25. In conse uence,

with the insertion ofa suitable imp ement through theselaterally extending branch- -openings into the vertical ways 31, the levers Cal , released.

4 flattened portion the numeral 33,

;and thus form a connection as lieing moved 30 may be engaged and moved inwardly so as to'efi'ect retraction of the slidable bolts 28 against tension" of their respective ex pansible coiled springs 29 in order that the over shot may be disconnected from'the upper end of the rod 10 andethe drill thus The slide bar or rod '7 which extends downwardly into the enlarged portion 5 of the longitudinal way is provided with a or plate 32 of awidth the width of such enlarged portion 5 of theway and capable of vertically therein, at times. Upon the opposite faces of this plate 32 and arranged in proximity to the OPPOSXtG sides or marginal portions thereof -areseries o spaced'tapered-ribs generally indicated by and between these ribs there are arranged screw receiving openings 34.

Link carrying or securing bars 35 are provided and as shown in the Figure 7 have corresponding to "transversely disposed pockets 'or recesses-36 formed therein and arranged in spaced, relation.corresponding lo the arrangement 0 ribs 323 carried upon the oppo- Thus, these bars with the opposite faces of the plate 32 at points adjacent the opposite sides of the-same, whereupon the tapered transverse pocketsor recesses 36 will fit over the-tapered ribs 33 between the the several bars 35". Interthreadei'l openings 37 are the plate plate 32 and ually screw with the threads of ,order that pivotal during its drilling operation;

by way of illustration,

f aligned eyelets 43, hence,

inclined bearing sur formed in the several link carryingbars 35 and are arranged coinpleuientally to the screw receiving openings. 34 in the plate 32, whereby set screws 38 may be first passed through said openings 34 and then engaged theadjacent openings 37 wherehy'the linkcarryingbars will be securely joined to the'opposite faces of the plate 32 the manner indicated Cutter or reai'ner carrying links 39 are received in pockets 40 formccl'inthe link carrying bar 35 and opening onto the inner sides or marginal portions of the same, as is also shown in the Figure 6; these links having eyelets formed in certain of their ends adapted, when inserted in the pocketsv 40, to be aligned with hearing pin openings 41 also formed in the link carrying bars 35 wherebypivot pins may be passed through the same and links, as indicated by the numeral 42, in connection as between the several link carrying bars and theirlrespective links 39 may 39, as shown in the Figure3, are or lengths tended through the oppositely disposed windows 6 formed in the'lower ortion of the drill body 1 andupon their outer ends; larger-eyelets'43are formed and are adapted to be inserted into ockets formed inthe inner ,side portions" 0 or reamers-to'be employed'upon the drill be seen that with engagement oi the ends 43 of the links 39 with the cutters or reamers, such elements will be pivotally connectedito the link carrying bars 35 carried upon the plate 32 ofithe slide rod :7

The improved-drill is either reamers or cutters in the windows 6 of the. drill body 1 and in'this particular embodimentof the invention, Ihave shown, a cutter indicated in its entirety by the numeral 44 and a reamer,

as above, stated, is

Each of these elements,

formed in its inner adapted .to have pockets side in which the-eyelet carrying ends 43 i of the. various links 39 are adapted to be bearing openings formed in both 44 and reaincr 45 and effecting pivota connection as bet-ween the links 39 and the cutter 44 or reamer 45, as the case may be.

In the Figures 1, 2 and 3, I have shown the drill as-being equipped with cutters 44 and as'will be noted, the upper and lower porthe cutter through said eyelets of the.

beefi'ected'. These links Thus, it will adapted to receive through the in the Figthe particular cutters f indicated in its entirety by the numeralv 45,

tionsof these cutters are provided with faces 47 such inclined bearing surfaces bein adapted to have sliding engagement with t is inclined bearing surfaces of guide pieces 48 having substantially permitted and in consequence, the cutters 44 will he moved inwardly towards each other riding over the inclined bearing surfaces 0 the guide pietes 48 until they have been ,entirely removed from the windows 6.

When so positioned, it will be understoodthat the lower portion of the drill body 1 may be ,then moved upwardly throuh the o '11 lower end of the drill stem 13 i' order t at the drill may be removed from the bore for repairs. or inspection, as may be required. However, when the drill is again lowered into the drill stem 13, the lower portion thereof will extend from the lower open end of said stem, as shown in'the Figure 3,

and the expansible coiled spring 12 will motion to cause downward sliding movement of the bar 7earrying the plate 32, thereby permitting further-pivotal movement of the connecting links 39 in order that the oppositely. disposed and similarly mov cutters Mmay be passed through the wmdows 6 of the drill body'andrextended, as shown. When in these extended positions, the cutters 44 will function, with rotation of the drill stem 13,-to carry out the desired boring or-drilling operation.

'To facilltate inter-changing of the cutters or reamers and their connection with the eyelet carrying end 43 of the links 39, the windows 6 formed in the drill body are. of widths greater than said cutters or reamers. Thus, the particular devices to be connected -to the drill may be readily engaged with the eyelet carrying ends 43 of the links 39,

whereupon reducer plates'50 are moved into that space occurring between one side of each of the windows 6 and the adjacent side of the particular cutter or reamer ree'eived therein; these plates carrying dove-tailed shaped ribs 51 upon one side thereof adapted -to be engaged in correspondingly formed grooves formed in the adjacent side of'each ofthe windows 6 whereby to afford positive connection of such reducer plates with the drill body; Furthermore, to prevent sliding displacement of the reducer lates 50 with respect to the windows 6, Ice ing screws 52 are adapted. to be passed through openings formed in thedove-tailed shapedfribs 51 into engagement with screw threaded openings formed in adjacent portions. of said drill body.

It is desirable that the drill he provided with positive means for lockin the cutters or ,rcamers in their distended tion, and to effect this, I slidahly arrange in horizontal ways formed adjacent the hexagonal upper portion- 2 of the drill body 1, oppositely disposed locking belts or pins 53, arranging expansible coiled springs 5e within such ways and about the adjacent portions of the pins whereby to normally exert inward thrusts to the same. Levers influence of theexpapsiblc coiled spring '12, suchkeepers or pockets willbecome aligned with the inner extended end of the oppo-.

sitely disposed bolt 53 and will be engaged di'illing posiw thereby. 'Hence, the slide rod 7 will be locked in its lowermost position and in con-. sequence, inward'movement of the cutters 44 or reamers 45 connected to the links 39 will I be prevented. However, when it isdesired to remove the drill from the drill stem 13, it. .Will be seen that with disengagement of the locking bolts or pins 14 from their respective keepers or pockets 19,upward movement-of the drill body through the drill stem'13.will be permitted and the outwardly extended levers 55 upon passing through'the lower open end of such drill stem will be caused to move inwardly and during such inward movement will impartoutward pulls 'totheir respective slidable spring pressed bolts or locking pins 53, thereby dis'en ag- I ing the inner ends from such pins from t elr respective keepers in the slide rod 7 and permitting the rod-to be moved u wardly, whereupon by reason of the pivotalcohnection of the cutters or reamers to the links 39 to the plate 32, such cutters orreamers will be caused to be drawn inwardly towards each other until they have been completely withdrawn from their extended positions and will not interfere with elevation of thelower portion of the drill body 'fromtho lower open end of the drill stem 13.

or nipple 59 adapted to he turned into engagement with a downwardly opening screw threaded pocket formed in-the lower end of the lower portion 3 of the drill 1. drill head is ters indicated vill be noted are arranged in positions provided with rotiitable cutwhereby the drill when engaged with the matter to be borerl pr drilled, will readily enter the same.

A 'drill head 58 is p vidta the (11-111 and carries thereon a screw tln-eadedcxtension y the nurheral 60, which, as.

inn

This j The cutters 60 comrise' rollers having cutter. serrations torme upon their peripheral portions while bearing openings 61 are formed therein and are adapted to receive the shanlc'portions of hearing pins 62 there- .through, such bearing pins being priovidQ:

with enlarged heads 63 having circular tapered beads 64 formed upon their inwardly disposed bevellcd sides and adapted to enter correspondingly formed grooves 65 umof screws 68, engaged therein. Because of this particular construction, it will be understood that the opposite sides of. the bearing opening 61 of the various cutters will be positively closed and-in conse quencc, the passage of sand, grit, or dirt into engagei'ncnt with the. anti-frictional bearing devices of such cutters will be prevented and therefore, premature dctcriora- 'tion of the cutters will be avoided.

The cutters. 44:, as shown. have elongated rotatable cutters 69 rotatably engaged with the outer side portions thereof, whereas the lower portions of the same are stepped and have other cutters 7O rotatably connected thereto by means of bearing pins or devices corres ondinp to the element indicated herein store-by the numerals 62, 63 and 67.

Thus, the passage of abrasive substances into engagement with the anti-frictionalbearings of the cutters "70 will be avoided.

The reaniers 45 are ada ted to be formed with chamfered cutting c gcs 71, while the lower and under portions of the same are formed, as indicated at 72, whereby they will eiicctually cut through mud and similar matter and at the sometime, will plaster or smooth the walls of the bore being made.

It is to be understood that various forms of drill heads may be connected to the lower end of the drill body 1, such as conditions or preference may dictate and in the majority of these drill heads, it is preferable to supply the same with a cooling fluid, such as water, whereby that heat generated thy friction during rotation of the drill will be kept at minimum. To carry out this ObJGCt, cooling fluid conveying and discharging ways-73 are formed within and extended longitudinally of the drill 1, opening onto the upper side. thereof, as shown in with fluid receiving and discharging ways tormed in the particular drill heed employed in connection w th the drill. Thus,

water will be discharged onto the drill head adjacent its various cutters and by consequenceycxcessive heat which is frequently caused by friction resulting from rotationof the drill willbe kept at minimum.

In operation of my improveddrill, the drill is lowered intothe drill stem to that positionas shown in the Figure 3, whereat the hexagonal upper portion 2 thereof will be snugly engaged; with the correspondingly formed lower end of the drill stem 13 and thus, adriving connection as between thetwo will be established. When the lower portion 3 of the drill body 1 has assed through the lower open end of the dri l stem 13 the slide rod 7 will immediately move to its lowermost position under influence of the expansiblc coiled spring 12, whereupon the cutters or rcamers connected to the v links 39 will be moved laterally to their 63-45 tended positions through the windows 6. \Vhen the slide rod 7 has reached its lower most position, the sliclable spring pressed locking bolts or pins will immediately engage in their respective keepers in such rod and in consequence, will serve to prevent any further upward movement thcreof or inward movement of the cutters or reamcrs connected to the links 39. Hence, proper functionin of the cutters or reamers during rotation 01? the drill will be ensured. Simultaneously with lowering of the hexagonal upper portion 2 of the drill into the lower end of the drill stem, it will be understood that the outwardly thrust slidable locking bolts or pins 14 will be engaged V with their respective keepers 9 as will the \Vhen it is desired 'to remove the drillfrom the drill stem 1, the over-shot device 25 is lowered into the stem 13 until it engages with the upper end of the (hill 1; the

lit

spring pressed slidable locking pins 28 e ngaging with the notched portions 11 formed in the upper end of the rod 10 and effecting' positive connection as between said over:

shot and the drill Simultaneously,.the, vwtically disposed pins 22 will be forced downwardly so that the inclined portions of,

their respective shoes 2.) will engage with. the corresponding lovers 1? connected to the locking bolts or pins 1-} and inovelthe same inwardly, thus efi'ecting retraction o fflsaid locking. bolts or pins 14: and disengaging the same from their respective keepers 'or pockets 19. At this time, an upward pull is imparted to the cable 26 connected to the over-shot device 25, whereupon the rounded head of the spring pressed-pins 20 will be automatically disengaged from their respective pockets or keepers in the inner side walls of the drill stem 13 and the drill is posed way therein,

then elevated. During movement of the lovers through the open lower end of the drill stem 13, the same will, of course be moved inwardly, thus disengaging their locking boltsor pins 53 from the slide rod 7 and permitting upward movement of said slide rod against the tension of the em .pansible coiled spring 12, whereby to'permit of pivotal movement of the link 35 and implement in the laterally extendingbranch openings of theopenings 31 whereby to cause inward movement of the levers 30 with the consequent retraction of their re: spective locking pins or bolts 28.

Manifestly. the construction shown is capahle of considerable modification and such modification as is within the scope of my claims, I consider within thcspirit of my invention.

I claim:

1. A drill comprising a body portion having an upwardly opening longitudinally disthe lower portion of which is enlarged and formed with oppositely arranged windows, a rod slidably received in said way carrying a flattened plate on its lower end, cutters pivotally connected to said plate and adapted, at times, to be extended through said windows, means for automatically locking said rod against sliding movement and operable to release the same upon upward movement of the drill, and a hit connected to the lower end of the drill.

2. A drill comprising a body portion having an upwardly opening longitudinally disposed way therein, the lower portion of which is enlargedand formed with oppositely arranged windows, a rod slidahly rceeived in said way carrying a flattened plate on its lower end, cutters movably connected to said plate adapted, at times, to be extended in opposite windows, means for automatically locking inward movement subsethe cutters against same to extended quently to movement of the positions and operable to release the cutter upon upward movement of the drill, and a bit connected to the lower end of said drill.

3, A drill comprising a'body portion having an upwardly opening longitudinally disposed way therein, the lower portion of which is enlarged and formed with oppositely arranged windows, arod'slidably reeived in said-way carrying a flattened plate on its lower end, oppositely moveable cut-' ters pivotally connected to id plate and directions through said adapted, at times to extended through saidwi ndows, means for automatically lockmg said cutters against movement subsequently to arrangement of the same throu h said windows and operable to release t 1e cutters upon upward movement of the drill, gndla bit connected to the lower end of said ri' 4. A drill comprising a body portionhavingan upwardly opening longitudinally disposed way therein, the lower portion of which is enlarged and formed with oppo sitelyarranged windows, a rod slidably ccived in said way carrying a flattened plate on its lower end, means for normally exerh in a downward thrust and pressure upon said rod, cutters pivotally connected to said plate and. moveable in op ite directions whereby they may be exten ed through-said windows, at times, means for automatically locking said rod against sliding'movement posed way therein, the lower portion of which is enlarged and formed with .opp0-' sitely arranged windows, a rod slidably received in said way carrying a flattened plate on its lower end, cutters havin their upper and lower portions bevelled pivotally con nected to said dplate and adapted, at times, to be extende through said windows by movement in opposite directions, means for automatically locking said cutters against movement subse uently to their movement through said win ows but operable to release the same upon upward movement of the drill, and a bit connected to the lower end of said drill.

c. A drill comprising a body onies having an upwardly opening longitudinally disposed way therein, the lower portion of which is enlarged and formed with oppositely arranged windows, a rod slidably received in said way carrying a flattened plate on its lower end, oppositely disposed and moving cutters pivotally connected to the opposite side portions of said plate and arranged adjacent its opposite faces, said outters adapted, at times, to be extended through said windows, means for automaticallyhlockin said cutters in their positions when exten ed through said windows, but operable to release the same upon upward movement of the drill. to the lower end of sai drill.

7. A drill comprising a body portion having an upwardly opening longitudinally dis posed way therein, the lower portion of which is enlarged and formed with oppond a bit connected I sitely disposed windows, a rod slidably re-- faces of said plate adjacent its opposite, sides, links pivotally connected tosaid bars and (i18 posed in opposite directions parallel to the opposite faces of said plate, cutters pivotally connected to the free ends of said links and movable, at times, through said Windows,-

means for locking said cutters in certain sitions against inward movement, but operable to release the same wherebyto permit inward movement thereof with upward movement of the drill, and a bit connected to the lower end of said drill.

8. A drill comprising a body portion having an upwardly opening longitudinally disposed .iway therein, the lower portion of which is enlarged and formed with oppositely disposed windows, a rod slidably receivedin said way carrying a'flattened plate on its lower end, cutters pivotally connected to the opposite sides and faces of said plate and adapted, at times, to be extendedthrough said windows, and automatically operable means for locking said cutters against inward movement subsequently to their extension through said windows but operable with upward movement of the drill to release said cutters and permit such inward movement of the same.

9. A drill comprising a body "portion having an upwardlyvopening longitudinally disposed way therein, the lower portion of which is enlarged and formed with oppo sitely arranged windows, a'spring pressed rod slidably received"in said way carrying a flattened plate on its lower end, oppositely moving cutters pivotally connected 'to the opposite sides andf'aces of said flattened plate and adapted, at times, to be extended throu h said windows, inwardly thrust slidable locking pins arranged in a portion of the drill body engageable with said rod, at times, to lock the same against sliding movement, and means carried upon the outer cndsof said locking pins engageable with a drill-stem upon upward movement of the drill thercthrouglr whereby to more said pins to their released ositions.

10. A drill comprising 'abody portion r having an upwardly opening longitudinally disposed way therein, the lower portion of which is enlarged and formed with oppositely disposed windows, a rod slidably' received in said way carrying a flattened plate on its lower'end, bars disposed longitudinally of said plate arranged upon its oppo-- site faces and adjacent its opposite sides,

oppositely disposed pairs of links pivotally V I connected to said bars, cutters pivotally connected to the free ends of said links and adapted, at times, to be extended ,throu 11 ried upon the outer ends of said pinsengageable with, a drill stem casing upon upward movement of the drill whereby to move said locking pins to their retracted position a and disengage said rod, and a drill bit car ried upon the lower end of the drill.

11. A drill comprising a body portion, cutters movablycarried by said drill and adapted to be extended therefrom, at times, and normally extended automatic locking pins carried upon the upper portion of said drill. engageable -with portions of the inner side of a. drill stem whereby to lock said .drill with relation to the stem, and means for effecting disconnection of said pins from the drill stem, at other times.

12. A drill comprising a body portion. cutters movably carried within said drill and adapted to be extended outwardly therey from, attim es, slidable-spring pressed locking'pins carried in the upper portion of said drill adapted to be automatically moaied outwardly into engagement with portions of the inner walls of a drill stem, levers carried on the inner ends of said pins, and vertically dis osed spring pressed pins carried by the dril and extending from the upper end thereof, adapted at times, to be depressed and to engage said levers of the first pins whereby to 'move the latter to retracted positions and disengaged from said drill. stem.

13. A drill comprising a body portion carrying movable cutters therein adaptedto be extended from the peripheral portions of the same, at times, means for automatically locking said cutters in their extended positions but operableto release the same upon upward movement of the drill in a dri l stem, s ring pressed slidable oppositely' disposed ocking pins carried in the upper portion of said drill body adapted to be engaged with portions of the inner walls of the drill stem whereby to connect said body to said stem, levers pivotally connected to the inner ends of'said locking ins, and vertically disposed pins carried i'nt e upper portion of said body extending upwardly from the same adapted, at times, to-be engaged with said levers whereby to retract said first pinv and disengage the same from said-inner walls of the drill stem.

14;:"A drill comprising a body portion having an upwardly opening longitudinally disposed way therein, the lower portion of which is enlarged and formed with oppositely arranged windows, a spring pressed Zillirod slidably rece 'wgdinsaid vay carrying a flattened plate on its Iowan-portion; oppositely mov%le' cutters arranged adjacent the 0Pp0S1l3Q -faC8S and opposite sides of said plate piyota'lly connected towns-"same and, adapted to be extended at times, through said windows'spring pressed slidable locking pins carried by the drill body engage- *inner wall of said drill stem, and a drill bit able, at times, with portions, of said rod, levers pivotally connected to the outer ends of said pins and adapted to extend beyond the adjacent sides of the drill body whereb to be engaged with the lower end of a dri l stem upon upward movement otthe drill portion of said drill body extending up- .wardly beyond the same and adapted, at

times, to be moved into engagement with the levers of said second mentioned locking pins whereby to retract the same, spring pressed supplemental docking pins slidably arranged in the upper portionof said dri l body, also engageable with portions of the connected to the lower end of said drill body.

15. A drill comprising a body ortion, oppositely moveabl cutters pivota ly connected to and arranged in the lower portion of said drill body adapted to be extended beyond the same, at times; the upper portion of said drill body being hexagonal m cross section and snugly receivable in the lower portion of a drill stem, means fol" automatically effecting connection between said drill stem and hexagonal portion of the drill body but adapted, at other times, to be automatically disengaged therefrom, and other automatic :means for securing said cutters in their extended positions, at times, but operableat' other times to permit movement of'the same to their innermost positions within thefirillbody, and a bit carried upon the lower end of said drill body.

In witness whereof I have hereunto set my hand.

Doi ALnHENRY MITCHELL. 

